docs: def backwards(apps, schema_editor):
      """
      Delete sample events, including derivative repeat and variation events.
      """
      titles = [
          'Daily Event',
          'Weekday Event',
          'Weekend Event',
          'Weekly Event',
          'Monthly Event',
          'Yearly Event',
      ]
      samples = EventBase.objects.filter(title__in=titles)
      samples.delete()